i think the answer is puppies
This is an opinion question and the answer depends on your definition of friendship. Their friendship is unusual but it is a close relationship nevertheless. Both characters sacrifice for one another. For example, George stays with Lennie due to the promise he's made to Lennie's aunt, and because he also subconsciously feels a need for Lennie's optimism. Lennie is willing to do whatever pleases George. George had a high amount of respect and love for Lennie, and it is why he chooses to kill him himself. As a friend, George does not want Lennie to die by the hands of Curly and he certainly doesn't want Lennie to be arrested.
1. Man v.s. Self
2. Man v.s. Nature
3. Man v.s. Man
4. Man v.s. Man
5. Man v.s. Man
Hope this helps!!! :)